This invention relates in general to vehicle trim components, and in particular relates to a method of manufacturing an airbag assembly and trim component.
The interior of a vehicle typically includes a multitude of components for covering various frameworks, instruments, and electrical devices mounted within the interior compartment of a vehicle. Examples of trim components include instrument panels, door panels, center consoles, overhead consoles, and other various interior panels for covering the sides, ceilings, and vertical pillars of the frame members of the vehicle.
The instrument panel is generally positioned underneath the windshield and attached to the frame of the vehicle behind the engine compartment. The instrument panel encloses various vehicle components, such as electrical and ventilation systems, audio systems, vehicle instrument gauges and displays, airbag assemblies, and auxiliary compartments.
In the past, trim components, such as instrument panels, were made of metal or plastic and commonly had rigid exterior upper and rear surfaces facing the interior of the vehicle. The upper and rear surfaces of the instrument panel are within reach and direct sight of the occupants of the vehicle. Recently, consumers have been demanding a more aesthetically pleasing exposed surface. It is also preferred that the tactile properties of the surfaces are also more pleasing, such as having soft or elastic properties compared to a relatively rigid surface. Thus, the outer surface areas of the trim components have been covered in a suitably soft material over the rigid structurally accommodating framework of the trim component.
In certain instances, the occupants of a vehicle may come into physical contact with portions of the trim components. During a vehicle impact condition, sudden large impact forces may be delivered to the occupant of the vehicle, such as in a rearward, frontal, or side impact. These forces may cause the head and limbs of the occupant to be forced against trim components and structures of the vehicle, thereby causing injury.
Various countermeasures have been taken to help reduce the degree of injury caused by impact conditions. For example, passive restraint systems having airbags and/or air curtains have been implemented into vehicles. Generally, such airbag assemblies are stored and packaged in deflated condition in storage areas within the passenger compartment of the motor vehicle. The airbag assemblies include sensors located at various points in the vehicle. Upon impact, the sensors are triggered thereby sending a signal to a gas generator or igniter. The gas generator operates to inflate the airbag when it receives a signal from the sensors. The airbags are located at various areas within the interior of the vehicle in which contact with the occupant is likely. For example, airbags are positioned in front of the driver and passenger locations, such as in the steering wheel and passenger side of the trim component or instrument panel. Air curtains may additionally or alternatively be included in such airbag assemblies, and may be positioned along the sides of the occupants, such as mounted at the edges of the headliner and propelled downwardly when inflated. Side air curtains have also been incorporated into the side portions of the seat backs.
When incorporating an airbag assembly into a trim component such as an instrument panel, the trim component includes an opening through which the airbag deploys when activated. It is generally desirable to include a mountable door or cover on the trim component to conceal the opening in the trim component. It is becoming increasingly common to provide a seamless or hidden airbag cover portion in the instrument panel that will reliably and safely tear upon deployment of the airbag, such that the passenger is protected. To this end, a tear seam has generally been provided in the airbag cover portion of an instrument panel to insure that the airbag will safely deploy.
Vehicle designers prefer to have a continuous surface on the front face of the trim component, whenever possible, so they would prefer to avoid having a part line or seam in the trim component. Thus, for trim components such as instrument panels, recently there has been an effort to achieve a “seamless” design wherein there is no indication on the front face of the instrument panel that the airbag is behind the instrument panel. To achieve this design, hidden tear seams or tear strips provided in the instrument panel are only provided on the under face, and not on the front face of the instrument panel.
The trim component should perform the utilitarian function of breaking apart along its tear seam to allow the airbag to exit through the airbag cover portion of the trim component when deployed. Preferably, the airbag cover portion of the trim component should not break apart, especially during cold deployment.
Thus, it is desirable to provide an improved method of manufacturing a trim component and airbag assembly in a “seamless” design that will deploy without undesirable failures, such as during cold deployment. It is also desirable to provide an improved method of manufacturing a trim component and airbag assembly that is cost effective and simplifies the manufacturing process.
In a known method of manufacturing an airbag assembly, a scrim material is used as a hinge to attach an airbag cover to the vehicle. A first end portion of the scrim material is coated in a plastic material. A second end portion of the scrim material is also coated in the plastic material. The first end portion of the scrim material is attached to the vehicle by a fastener disposed through the scrim and plastic material. Next, the second end portion of the scrim material is vibration welded to the instrument panel. An intermediate portion of the scrim material is disposed between the first and second portions. The intermediate portion is not coated in plastic material. The uncoated intermediate portion of the hinge material acts as a flexible hinge between the vehicle and the airbag cover. Although this method has worked successfully, the manufacture of this hinge is expensive and time intensive, because of the numerous steps required to coat only the first and second end portions of the scrim to produce the hinge.